Salivary zinc has been measured for the first time in normal subjects and in patients with various abnormalities of taste acuity. In general, salivary zinc concentrations in patients with idiopathic hypogeusia are significantly lower than in subjects with normal taste acuity. A new syndrome of acute zinc depletion has been elucidated. In addition to changes in several sensory modalities these patients suffer from severe cerebellar dysfunction including intention tremor, positive Romberg sign and ataxia. Treatment with zinc ion corrects these abnormalities within 24-48 hours. The role of copper and zinc metabolism has been investigated in several disease states. The data suggest that patients with breast cancer exhibit lower than normal serum concentrations of zinc.